Tolkien explored various possibilities regarding the exact interpretation of the elements occurring in the name: it is either Azanul + bizar or Azan+ûl+bizar, though the whole was to somehow express "Dimrill Dale".

Tolkien stated that "the Common Speech form is an accurate translation: the valley of the dim (overshadowed) rills that ran down the mountainside".[3] In another point it is given as "Vale of Dim Streams" with three elements.[4]

The first interpretation says that azan "shadows, dimnesses", -ul genitive marker and bizar "streams, rills"; in this interpretation it means "rills of shadows", and the word "dale" is understood (the full name being duban Azanulbizar).[5]

According to the second interpretation, bizar means "dale" and ul "rill(s), streams".[4]